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NAME | C SYNOPSIS | DESCRIPTION | SEE ALSO | COLOPHON |
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PMOPENLOG(3) Library Functions Manual PMOPENLOG(3)
pmOpenLog - create a log file for diagnostics and debug output
#include <pcp/pmapi.h>
FILE *pmOpenLog(const char *progname, const char *logname,
FILE *oldstream, int *status);
cc ... -lpcp
pmOpenLog reassigns the standard I/O stream oldstream (normally
stderr) to be associated with the file logname.
If logname is not "-" and the file already exists, it will be re‐
named to logname.prev else removed. Due to permissions restric‐
tions, the rename or removal may not succeed, but in the common
use cases logname.prev remains with the contents of the previous
version of logname. Then logname is recreated if possible (to
ensure correct ownership and permissions from the caller to
pmOpenLog).
As a special case, if logname is "-" then no renaming, removal or
reopening is performed and the function simply sets status to 1
and returns oldstream. This is useful when the caller wants di‐
agnostics on oldstream stream (normally stderr) rather than a
file, e.g. pmlogger -l- or pmcd -f -l-. Logging to stderr is
also useful for PMDAs in a containerized environment where it is
beneficial for all PMDA logs to be written to pmcd's stderr
stream (and thus to a single destination), whether that is a file
such as pmcd.log or the original stream inherited from the shell.
On return, the function value is the standard I/O stream, possi‐
bly replacing oldstream. In the event of an error, the return
value will be oldstream unchanged and status will be 0.
For success, status is 1, and a standard preamble is written to
logname
Log for progname on hostname started date and time
and an atexit(3) handler is installed to write the postscript
message to logname
Log finished date and time
when the processes exits.
progname is only used to annotate messages.
atexit(3) and freopen(3).
This page is part of the PCP (Performance Co-Pilot) project. In‐
formation about the project can be found at ⟨http://www.pcp.io/⟩.
If you have a bug report for this manual page, send it to
pcp@groups.io. This page was obtained from the project's
upstream Git repository
⟨https://github.com/performancecopilot/pcp.git⟩ on 2024-06-14.
(At that time, the date of the most recent commit that was found
in the repository was 2024-06-14.) If you discover any rendering
problems in this HTML version of the page, or you believe there
is a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
Performance Co-Pilot PCP PMOPENLOG(3)
Pages that refer to this page: pmnotifyerr(3), __pmnotifythrottle(3)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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